Amai Seikatsu -Saikou no Gibo to Saikou no Gishimai-

Kyosuke lost his mother when he was a kid and he has been living with his father since then. But one day, he gets remarried to a young and beautiful woman, Yuki, who has two pretty daughters, Manami and Risa. Though Kyosuke is confused to live with them, they gently and openly take care of him. Kyosuke isn't immune to girls, so he often gets sexually excited by smelling their body scent even when eating breakfast. One day, Risa finds it and secretly gives him a blowjob as a joke. Kyosuke soon ejaculates under the table.... Like this, his erotic life with them starts...